JP6038224B2 - Manufacturing method of progressive power lens - Google Patents

Description

  The present invention relates to a method for manufacturing a progressive-power lens.

  The progressive-power lens is an auxiliary spectacle lens for adjusting power when the adjusting power of the eye declines and near vision becomes difficult. In general, in a progressive-power lens, a distance vision correction region (hereinafter referred to as “distance portion”) located above the lens and a near vision correction region (hereinafter referred to as “near vision”) located below the lens when worn. And a progressive region (hereinafter referred to as “intermediate portion”) in which the refractive power continuously changes between both regions. In the present invention, notations such as “upper”, “lower”, “horizontal” and “vertical” indicate the positional relationship in the lens when worn, and for example, the lower part of the distance part is the distance part. A region close to the middle portion is shown in FIG. In the progressive-power lens, a lens that is easy to wear is ideal because it has a wide clear vision area, little distortion, distortion, etc. in all areas of the distance portion, the intermediate portion, and the near portion.

  In the conventional progressive-power lens, the optical performance is often evaluated by the distribution formed by the surface astigmatism of the progressive-power surface and the surface added average refractive power. Furthermore, it is considered that the main purpose is to secure a distribution area where the astigmatic difference is less than the human eye can accept, that is, a so-called clear vision area, and the range where aberrations should be suppressed on the lens is limited. Therefore, it is a very effective guide for designing a progressive-power lens that cannot escape from the occurrence of aberrations.

  By the way, it is said that the human eye is more sensitive to the amount of change than the absolute value of aberration. Therefore, when designing a progressive-power lens, if not only the absolute amount of aberration but also the amount of variation in aberration with respect to line-of-sight movement can be suppressed, the unpleasant feeling of distortion and distortion that can be felt when using a progressive-power lens is achieved. It can be reduced.

  For example, in Patent Document 1, a point where the surface astigmatism is maximized is found in the lens surface, and the value is changed by controlling the ratio of the value of the surface astigmatism and the distance from the geometric center of the lens to the point. A progressive power lens technology has been disclosed in which the amount is slow and a wide field of view is ensured in the near vision region and the intermediate vision region.

JP-A-11-194307

    When actually looking with the eyes, it can be considered to move the line of sight in various directions, and in particular, since characters are often written vertically or horizontally, there are many opportunities to move the line of sight vertically and horizontally. Therefore, it is considered effective to control the astigmatic difference in the vertical and horizontal directions and the fluctuation amount of the surface added average refractive power. However, in the conventional example, even though it is possible to control the point where the surface astigmatism is maximum in the lens surface, the variation of the surface astigmatism up to the maximum point is suppressed, and the vertical direction of the line of sight It was difficult to suppress the amount of fluctuation in the horizontal direction.

  In view of the circumstances as described above, an object of the present invention is to provide a manufacturing method of a progressive power lens that can obtain a good appearance with respect to line-of-sight movement.

According to a first aspect of the present invention, there is a progressive power lens having an outer surface that is a refractive surface on the object side in a worn state and an inner surface that is a refractive surface on the eyeball side in a worn state, the outer surface and the At least one of the inner surfaces is provided above the lens in the wearing state, and is a distance portion suitable for relatively far vision, and provided in the lower portion of the lens in the wearing state, and is a near portion suitable for relatively near vision. It is formed in a progressive surface shape having a use part, and a progressive part provided between the distance part and the near part and progressively changing the surface refractive power from the distance part to the near part. In the manufacturing method of the progressive-power lens which is,
Arbitrary point on the progressive-power surface that is at a position x (mm) in the horizontal direction in the lens wearing state from the geometric center of the lens surface and at a position y (mm) in the vertical direction in the lens wearing state from the geometric center Centering on Q (x, y), the average of the surface astigmatism of the line segment region having a width of D (mm) in the horizontal direction in the lens wearing state

  When the position of the near center in the vertical direction in the lens wearing state from the geometric center is yn, | x | ≦ 15 is satisfied and y = 0, y = yn × 0.25, y = yn In an area satisfying × 0.5, y = yn × 0.75 or y = yn, the average of the surface astigmatism is obtained at intervals of Δx, and the surface astigmatism at Q (x, y) The horizontal inclination in the average lens wearing state of

としたとき、処方で指定された加入度をＡＤＤとすると、

When the addition specified in the prescription is ADD,

Designed to satisfy the requirements of
The surface astigmatism on the main meridian curve passing from the geometric center through the near center and the far center increases from the top to the bottom of the lens,
The plane astigmatism on the main meridian curve is less than add-up x 0.25 at the near center;
In addition, there is a method of manufacturing a progressive power lens that is designed so that there is only one point where the astigmatism difference on the main meridian curve is an addition power of 0.25 below the near center. Provided.

  According to the aspect of the present invention, there is provided a method for manufacturing a progressive-power lens capable of obtaining a good appearance with respect to line-of-sight movement.

The figure which shows the outline | summary of the area | region division of the progressive multifocal lens designed symmetrically. It is a schematic diagram of the area | region division of an asymmetric type progressive multifocal lens. The figure which shows the progressive-power lens for left eyes concerning embodiment of this invention. The figure which shows the progressive-power lens for left eyes concerning embodiment of this invention. The figure which shows the characteristic of the progressive-power lens which concerns on the comparative example with respect to this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on the comparative example with respect to this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on the comparative example with respect to this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on the comparative example with respect to this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on this embodiment. The figure which shows the characteristic of the progressive-power lens which concerns on this embodiment.

  An embodiment of the present invention will be described. In the following description, the unit of refractive power is represented by diopter (D) unless otherwise specified. Further, in the following description, when the progressive power lens is described as “upper”, “lower”, “upper”, “lower”, etc., the glasses are used when the progressive power lens is processed for spectacles. It is based on the positional relationship of the lenses when worn. Also in the following drawings, the positional relationship (up / down / left / right) of the lens is the same as the positional relationship (up / down / left / right) with respect to the paper surface. Of the two refracting surfaces constituting the lens, the object side surface is referred to as an “outer surface” and the eyeball side surface is referred to as an “inner surface”.

FIG. 1 is a diagram showing an outline of a region section of a progressive power lens LS1 designed symmetrically.
The progressive-power lens LS1 shown in FIG. 1 includes a distance portion F located above when worn, a near portion N below, and an intermediate portion P whose refractive power continuously changes between both regions. It has. As for the shape of the lens surface, the intersection line MM ′ between the section along the meridian running vertically from the top to the bottom of the lens surface and the lens surface on the object side (opposite to the eye) is the addition of the lens, etc. It is used as a reference line for expressing specifications, and is also used as an important reference line in lens design. In the progressive-power lens thus designed symmetrically, the distance center OF of the distance portion F, the distance eye point E that is a fitting point, the geometric center OG of the lens surface, and the near center ON are the references. It is on the center line MM ′.

  FIG. 2 shows a progressive power lens (hereinafter referred to as an “asymmetric type progressive power lens”) in which the near portion N is arranged asymmetrically in consideration of the fact that the near center ON is closer to the nose side when the lens is worn. ) It is a schematic diagram of a region classification of LS2. Also in the asymmetrical progressive-power lens LS2 as shown in FIG. 2, the cross section passing through the distance center OF of the distance portion F, the distance eye point E, the geometric center OG of the lens surface, and the near center ON, and the object side lens A center line MM ′ that is an intersection line with the surface is used as a reference line.

In the present embodiment, these reference lines are collectively referred to as “main meridian curve”. The center of the distance portion F and the center of the near portion N are positions to be used as a reference when measuring the lens power. The distance measurement reference point is called the distance center OF, and the near measurement reference point is used for near purposes. Called center ON. Furthermore, the surface average refractive power at the distance center OF is a base curve, and the average spherical power of the transmitted light passing through the distance center OF is the reference average spherical power (hereinafter referred to as “distance power”) in the distance portion. And
Usually, the near vision center ON coincides with the near vision eye point. However, the distance center and the near center here mean not a geometric center in each region but a functional center at the time of measuring and wearing the lens.

  In this embodiment, the surface average refractive power (hereinafter referred to as “surface refractive power”) and the surface astigmatism difference (hereinafter referred to as “astigmatic difference”) are the maximum principal power at any point on the progressive power surface. When the curvature is ψmax, the minimum principal curvature is ψmin, and the refractive index of the lens is n, they are expressed by the following equations (a) and (b), respectively.

Surface power = (ψmax + ψmin) × (n−1) / 2 (a)
Astigmatic difference = (ψmax−ψmin) × (n−1) (b)

  Furthermore, in this embodiment, the surface addition average refractive power (hereinafter referred to as “surface addition power”) is a surface power obtained by subtracting the base curve from the surface power at any point on the progressive power surface. is there.

  For progressive-power lenses, positive surface power (or spherical power) is continuously added from the distance center OF toward the near center ON on the main meridian curve MM ′ that passes through almost the geometric center of the lens. Then, the value obtained by subtracting the surface refractive power (or spherical power) of the distance center OF from the surface refractive power (or spherical power) of the near vision center ON where the additional surface refractive power (or additional spherical power) is substantially maximized. This is called the addition of a progressive power lens.

  When a human sees things with the eyes, a light beam corresponding to the pupil diameter is imaged on the retina by the eyeball optical system, so that only the light rays that pass through one point on the lens surface do not affect the way they are seen. Therefore, when considering variations in surface astigmatism and surface additional average power, the amount of variation in surface astigmatism and surface additional average power between any point on the progressive power surface and the adjacent point is calculated. Rather than seeing, it is considered that it is more effective to look at the fluctuation amount of the average value in the line segment region including the point to be measured and having a width in the direction of moving the line of sight.

  Therefore, in the present invention, in order to take into account fluctuations of aberrations at any point on the lens surface with respect to the movement of the line of sight, the surface within the line segment region of the average calculation width D centered at any point in the direction of movement of the line of sight Taking the astigmatic average (shown by the following [Equation 10]) and the surface added average refractive power average (shown by the following [Equation 11]), the surface astigmatic difference average and the surface added average refractive power average of the line-of-sight movement direction We focused on how the tilt fluctuated.

  Here, if the average calculation width D is increased, the average is calculated in a wide range, and as a result, the surface astigmatic difference average and the surface additional average refractive power average are smoothed. If the average calculation width D is reduced, the surface astigmatism average and the surface added average refractive power average tend to be affected by minute fluctuations.

  In the present embodiment, it is preferable to make the size equivalent to the pupil diameter on the lens surface coincide with the average calculation width D in order to take a form more suitable for actual lens use. The pupil diameter is said to be 2 to 6 mm, although it varies depending on the age and ambient brightness, and is said to be about 4 mm in normal times. In the present embodiment, the average calculated width D is preferably 6 mm or less, and more preferably 4 mm in accordance with general use conditions.

  In a distance portion region of a general progressive-power lens, the amount of variation in the values of surface astigmatism and surface added average refractive power is suppressed. For this reason, it is often the case that a sense of incongruity associated with a change in aberration with respect to line-of-sight movement is not felt so much. On the other hand, in the progressive area and the near area, the amount of variation in both the surface astigmatism and the surface added average refractive power tends to increase due to the nature of the progressive-power lens. Pleasure may occur.

  For example, in the progressive region, the surface added average refractive power changes progressively, and the surface astigmatism may vary greatly. In general progressive-power lenses, the surface astigmatism on the main meridian curve is very well suppressed even in the progressive region, but the surface non-surface astigmatism is slightly distant from the main meridian curve in the progressive region. There was a region where the fluctuation of the point gap was large, and this region was thought to have a significant effect on the movement of the line of sight.

  Further, when considering a situation in which an object is viewed from the progressive area to the near area, a case of browsing a magazine is assumed. In that case, although there are some differences depending on the center thickness of the lens and the curvature of the base curve, assuming that the magazine is viewed at a distance of about 30 to 40 cm, the horizontal width on the progressive power surface corresponds to about 30 mm.

In the present embodiment, in order to suppress the fluctuation of the surface astigmatism with respect to the horizontal line-of-sight movement, when the position in the vertical direction in the lens wearing state from the geometric center of the near vision center is yn,
Satisfying | x | ≦ 15,
y = 0, y = yn × 0.25, y = yn × 0.5, y = yn × 0.75 or y = yn
In the line segment region that satisfies the following, [Equation 12] is satisfied.

Further, in the present embodiment, in order to suppress the variation of the surface added average refractive power with respect to the movement of the line of sight in the horizontal direction, when the position in the vertical direction in the lens wearing state from the geometric center of the near vision center is yn,
Satisfying | x | ≦ 15,
y = 0, y = yn × 0.25, y = yn × 0.5, y = yn × 0.75 or y = yn,
In the line segment region that satisfies the following, [Equation 13] is satisfied.

Further, in the present embodiment, in order to suppress the variation of the surface astigmatism with respect to the vertical line-of-sight movement, when the position in the vertical direction in the lens wearing state from the geometric center of the near vision center is yn,
While satisfying yn ≦ y ≦ 0,
x = -15, x = -10, x = -5, x = 5, x = 10 or x = 15,
The following [Equation 14] is satisfied in the line segment region satisfying

  In the present embodiment, the distance in each direction in the wearing state is based on the geometric center of the lens, and in the vertical direction in the wearing state, takes a positive sign upward and a negative sign below. In the horizontal direction in the wearing state, a positive sign is taken on the ear side and a negative sign is taken on the nose side.

  FIG. 3 is a diagram showing the progressive power lens for the left eye according to the present embodiment, and is a diagram for explaining a cross-sectional line represented by an intersection line between a horizontal plane and a refractive surface in a lens wearing state. is there. In the present embodiment, the distribution of the horizontal inclination CXa of the surface astigmatism average of each progressive-power lens and the distribution of the horizontal inclination PXa of the surface addition refractive power average are shown along this cross-sectional line. .

  In FIG. 3, H1 is a cross-sectional line passing through the geometric center OG, and H5 is a cross-sectional line passing through the near center ON. Further, when the vertical position from the geometric center OG of the near center ON is yn (mm), the vertical position y from the geometric center OG is yn × 0.25, yn × Cross-sectional lines at 0.5 and yn × 0.75 are shown. Hereinafter, in the present embodiment, the present invention will be described by focusing on the progressive-power lens for the left eye, but the same applies to the progressive-power lens for the right eye.

In the present embodiment, the horizontal inclination CXa of the surface astigmatism average and the horizontal inclination PXa of the surface additional refractive power average were obtained as follows.
First, the surface astigmatism and the surface additional refractive power are measured at intervals of Δx = 1 mm along the cross-sectional lines H1 to H5, and the point is centered at the measured arbitrary point (x, y) ( x-2,
y), (x−1, y), (x, y), (x + 1, y), (x + 2, y), the point (x, y) ) The surface astigmatism average (the following [Expression 15]) and the surface added refractive power average (the following [Expression 16]) were calculated.

さらに、点（ｘ，ｙ）を中心とした（ｘ−１、ｙ）、（ｘ，ｙ）、（ｘ＋１，ｙ）の三点のＣｘ、Ｐｘの回帰直線の傾きＣＸａ（ｘ，ｙ）及びＰＸａ（ｘ，ｙ）をそれぞれ算出した。ここで、ＣＸａ（ｘ，ｙ）については、下記［数１７］で表され、ＰＸａ（ｘ，ｙ）については、下記［数１８］で表される。

Furthermore, Cx at three points (x-1, y), (x, y), (x + 1, y) centered at the point (x, y), the slope CXa (x, y) of the regression line of Px, and PXa (x, y) was calculated respectively. Here, CXa (x, y) is represented by the following [Equation 17], and PXa (x, y) is represented by the following [Equation 18].

  In the present embodiment, the average calculation width D is 4 mm. However, the average calculation width D is not limited to this value, and the same effect can be obtained if the size is equivalent to the pupil diameter. In this embodiment, the distance Δx between CXa and PXa is set to 1 mm. However, when the surface astigmatism difference of the progressive power lens and the distribution of the surface added refractive power are observed, if the inflection point is not very large, the distance Δx is made fine. There is no need, and there is no problem even if it is discrete as in this embodiment.

  FIG. 4 is a diagram showing a progressive power lens for a left eye according to an embodiment of the present invention, and illustrates a longitudinal section line represented by a line of intersection between a vertical plane and a refractive surface in a lens wearing state. FIG. In this embodiment, the surface astigmatism distribution of each progressive-power lens is shown along this longitudinal cross section line. In FIG. 4, V1 to V7 have positions x from the geometric center OG of −15 (mm), −10 (mm), −5 (mm), 0 (mm), 5 (mm), 10 (mm), The longitudinal section lines at 15 (mm) are shown.

In the present embodiment, the vertical inclination CYa of the surface astigmatism average is obtained as follows.
First, the surface astigmatism difference and the surface additional refractive power are measured at intervals of Δy = 1 mm along the longitudinal section lines V1 to V5, and the point is centered at the measured arbitrary point (x, y) ( x, y-2), (x, y-1), (x, y), (x, y + 1), and (x, y + 2) from the value of the surface astigmatism of the five points, the point (x, y) The surface astigmatic difference average (shown by [Equation 19] below) was calculated.

  Further, the slope of the regression line of Cy at three points (x, y-1), (x, y), and (x, y + 1) with the point (x, y) as the center is calculated as the horizontal of the astigmatic average. The direction inclination Cya (x, y) was used. Here, the horizontal inclination CYa (x, y) of the surface astigmatism average is expressed as in the following [Equation 20].

  In the present embodiment, the average calculation width D is 4 mm. However, the average calculation width D is not limited to this value, and a similar effect can be obtained as long as the size is equivalent to the pupil diameter. In this embodiment, the CYa interval Δy is set to 1 mm. However, in view of the surface astigmatism difference and the surface added refractive power distribution of the progressive addition lens, it is necessary to reduce the inflection point if there are not many inflection points. There is no problem even if it is discrete as in this embodiment.

  FIG. 5 is a distribution diagram of the slope of the surface astigmatism average and the slope of the surface added refractive power average along the cross-sectional lines H1 to H5 as comparative examples for the present embodiment. In FIG. 5, the horizontal axis indicates the horizontal position x (mm) from the geometric center in the wearing state. The horizontal position x has a positive sign on the ear side and a negative sign on the nose side. In addition, the slope of the surface astigmatism average is indicated by a solid line, the slope of the surface addition refractive power average is indicated by a broken line, and the slope of the surface astigmatism average and the slope of the surface addition power average are D (diopter) / It is shown in mm. As will be described later, in the progressive-power lens according to the comparative example according to the prior art, the surface refractive power in the distance portion is designed to be substantially equal to the base curve.

  FIG. 6 is a distribution diagram of the average astigmatic difference slope along the longitudinal sectional lines V1 to V7 as a comparative example with respect to the present embodiment. In FIG. 6, the horizontal axis indicates the position y (mm) in the vertical direction from the geometric center OG in the wearing state. The position y in the vertical direction has a positive sign on the upper side and a negative sign on the lower side. In addition, the slope of the surface astigmatism average is indicated by D (diopter) / mm.

  In the progressive-power lens shown in FIGS. 5 and 6, the outer diameter φ = 60 mm, the base curve BC = 4.00 diopter, the addition ADD = 2.00 diopter, and the refractive index ne = 1 of the lens. .67, and the position of the near center ON is located 13.5 mm below the geometric center OG of the lens.

  In the progressive-power lens shown in FIG. 5, it can be seen that the fluctuation of the average astigmatic difference average and the average additional refractive power average change are large, and the tendency is different for each cross-sectional line. In other words, when this lens is used, there is a region where it is felt uncomfortable when the line of sight moves in the horizontal direction in the progressive portion.

  Further, in the progressive-power lens shown in FIG. 6, it can be seen that the variation of the average astigmatism average inclination is large, and the tendency is different for each longitudinal section line. That is, when this lens is used, there is an uncomfortable feeling when the line of sight is moved in the vertical direction.

FIG. 7 is a distribution diagram of the surface astigmatism difference of the progressive addition surface of the progressive addition lens according to the comparative example.
In the progressive-power lens shown in FIG. 7, since the region where the surface astigmatism difference is maximum is on the side of the progressive portion and the contour line interval is narrow in the central region, the inclination of the surface astigmatism difference in the horizontal and vertical directions. It can be seen that is large.

  FIG. 8 is a distribution diagram of the surface addition refractive power of the progressive addition surface of the progressive addition lens according to the comparative example. In the progressive-power lens shown in FIG. 8, since the horizontal width of the area of surface addition power 1.0 is narrow, it can be seen that the slope of the surface addition power in the horizontal direction is large.

  FIG. 9 is a distribution diagram of the gradient of the surface astigmatism average and the gradient of the surface additional refractive power average along the cross-sectional lines H1 to H5 of the progressive-power lens according to the present embodiment. In FIG. 9, the horizontal axis indicates the horizontal position x (mm) from the geometric center in the wearing state. The horizontal position x has a positive sign on the ear side and a negative sign on the nose side. In addition, the slope of the surface astigmatism average is indicated by a solid line, the slope of the surface addition refractive power average is indicated by a broken line, and the slope of the surface astigmatism average and the slope of the surface addition power average are D (diopter) / It is shown in mm.

  FIG. 10 is a distribution diagram of the average astigmatic difference slope along the longitudinal sectional lines V1 to V7 of the progressive-power lens according to this embodiment. In FIG. 10, the horizontal axis indicates the position y (mm) in the vertical direction from the geometric center in the wearing state. The position y in the vertical direction has a positive sign on the upper side and a negative sign on the lower side. In addition, the slope of the surface astigmatism average is indicated by D (diopter) / mm.

  In the progressive-power lens according to the present embodiment, the outer diameter φ = 60 mm, the base curve BC = 4.00 diopter, the addition ADD = 2.00 diopter, and the refraction of the lens, as in the comparative example. The ratio ne = 1.67, and the near center ON is located 13.5 mm below the geometric center OG of the lens.

  Referring to FIG. 9, it can be seen that the progressive power lens according to this example satisfies the following [Equation 21] and [Equation 22] in a region where 0 ≦ y ≦ yn is satisfied.

  Referring to FIG. 10, it can be seen that the progressive power lens according to the present example satisfies the following [Equation 23] in a region where | x | ≦ 15.

  FIG. 11 is a distribution diagram of the surface astigmatism of the progressive addition surface of the progressive addition lens according to the present embodiment. Referring to FIG. 11, in the progressive-power lens according to the present embodiment, the lateral astigmatism difference on the side of the progressive portion is suppressed, and the increase in the horizontal and vertical directions of the astigmatic difference becomes slow. I understand that.

  FIG. 12 is a distribution diagram of the surface addition refractive power of the progressive addition surface of the progressive addition lens according to the present embodiment. Referring to FIG. 12, it can be seen that the horizontal width of the contour line having a surface addition refracting power of 1.0 is widened, and the amount of change in the horizontal direction is suppressed.

  A specific example of the above [Formula 21] will be described with reference to the following [Table 1]. [Table 1] shows the value of [Equation 21] in the progressive-power lens according to this embodiment. In [Table 1], the cross-sectional lines H1 to H5 are shown in the vertical direction, and the horizontal position x (mm) is shown in the horizontal direction.

  As shown in [Table 1], it can be seen that the progressive power lens according to the present embodiment satisfies the above [Equation 21] in a region where 0 ≦ y ≦ yn.

  A specific example of the above [Equation 22] will be described with reference to the following [Table 2]. [Table 2] shows the value of [Equation 22] in the progressive-power lens according to this embodiment. In [Table 2], the cross-sectional lines H1 to H5 are shown in the vertical direction, and the horizontal position x (mm) is shown in the horizontal direction.

  As shown in [Table 2], it can be seen that the progressive power lens according to the present embodiment satisfies the above [Equation 22] in a region where 0 ≦ y ≦ yn.

  A specific example of [Equation 23] will be described with reference to [Table 3] below. [Table 3] shows the value of [Equation 23] in the progressive-power lens according to this embodiment. In [Table 3], a vertical position y (mm) is shown in the vertical direction, and vertical cross-sectional lines V1 to V7 are shown in the horizontal direction.

  As shown in [Table 3], it can be seen that the progressive power lens according to the present embodiment satisfies the above [Equation 23] in a region satisfying | x | ≦ 15.

  As described above, according to the present embodiment, the surface astigmatism and the surface addition are optimized by optimizing the optical performance in consideration of the surface astigmatism of the surface and the fluctuation amount of the surface added average refractive power. It is possible to obtain a progressive power lens that can suppress the amount of fluctuation of the refractive power and that can be viewed without any sense of incongruity even if the line of sight is moved in the horizontal direction or the vertical direction.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and modifications can be made as appropriate without departing from the spirit of the present invention.

LS1, LS2 ... Progressive power lens F ... Distance portion N ... Near portion P ... Intermediate portion MM '...
Main meridian curve OF ... Center for distance E ... Eye point for distance OG ... Geometric center ON ... Center for near use

Claims (2)

A progressive-power lens having an outer surface that is a refractive surface on the object side in a worn state and an inner surface that is a refractive surface on the eyeball side in a worn state, wherein at least one of the outer surface and the inner surface is in a worn state Provided in the upper part of the lens and relatively suitable for far vision, the near part provided in the worn state under the lens and relatively suitable for near vision, the distance part and the near part. In a manufacturing method of a progressive power lens formed in a progressive surface shape having a progressive portion that is provided between the use portions and progressively changes the surface refractive power from the distance portion to the near portion,
Arbitrary point on the progressive-power surface that is at a position x (mm) in the horizontal direction in the lens wearing state from the geometric center of the lens surface and at a position y (mm) in the vertical direction in the lens wearing state from the geometric center A line segment having an average calculated width D in the horizontal direction in the lens wearing state, with Q (x, y) being the center, and an average calculated width D (mm) corresponding to the size of the pupil diameter on the lens surface being 2 to 6. The average of the area astigmatism of the area

age,
When the position of the near center in the vertical direction in the lens wearing state from the geometric center is yn, | x | ≦ 15 is satisfied,
y = 0, y = yn × 0.25, y = yn × 0.5, y = yn × 0.75 or y = yn,
In the area that satisfies
The average of the surface astigmatism is obtained at intervals of Δx, and the horizontal inclination in the lens wearing state of the average of the surface astigmatism at Q (x, y) is calculated.

When
If the addition specified in the prescription is ADD,

Designed to satisfy the requirements of
The surface astigmatism on the main meridian curve passing from the geometric center through the near center and the far center increases from the top to the bottom of the lens,
The plane astigmatism on the main meridian curve is less than add-up x 0.25 at the near center;
In addition, the progressive power lens manufacturing method is designed so that there is only one point on the main meridian curve where the astigmatism difference is addition power × 0.25 below the near center . Method for manufacturing a progressive-power lens according to claim 1, wherein the diameter of the lens is 60 mm.

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